Various types of programmable announcement and reminder systems have been developed to play recorded audio messages at scheduled times or on scheduled dates. Examples include store announcement systems which use recorded announcements to inform customers of special sale events and other promotions (in some cases by interrupting background music that is normally played over store loudspeakers), and personal reminder systems which play recorded messages to remind the user of important dates or obligations. Generally, these systems utilize magnetic tape as the storage medium for the recorded messages, together with some type of memory or addressing system for advancing the tape to the proper position when a desired message is to be played. In some systems, messages are scheduled to be played at specific times or on specific days, while in other systems messages are played at predetermined intervals throughout the day. In the latter type of system, the interval between successive messages may be variable.
In the relatively simple types of programmable announcement and reminder systems described above, the possibility of conflicts between messages which are scheduled to be played at the same time does not ordinarily arise. In some systems, for example, fixed time slots are provided for the recorded messages, either on the magnetic tape itself or in the memory or control circuitry used to control the movement of the tape. Since a time slot assigned to one message ordinarily cannot be used for another, conflicts or overlap between messages cannot occur. Although it is possible in some systems to schedule more than one message to be played during the same time slot, the messages are usually short enough that they can all be played in sequence during the same time slot without overlapping the next time slot. Again, therefore, the possibility of conflicts between messages is eliminated.
Although announcement and reminder systems of the types described above are useful in some instances, a need exists for a more versatile type of automated announcement system which allows for more flexible scheduling of announcements and is not constrained to operate with fixed time slots or short message lengths. For example, it may be desirable to schedule different announcements to occur at different intervals (e.g., every 10 minutes for one type of announcement and every hour for another type of announcement), and to begin and end these announcements at different times of the day. It may also be desirable to establish general scheduling parameters that apply to all announcements, such as a minimum time interval between successive announcements and a maximum number of announcements that can be stored at a given time. Moreover, it may be desirable to change these scheduling parameters from time to time. Under these circumstances, it may be difficult or impossible to anticipate and prevent conflicts between messages when the messages are initially recorded or scheduled.
Other features that would also be desirable in an automated announcement system are similarly not found in the systems proposed previously. For example, it may be desirable to require the use of security passwords to operate the system, so that only authorized users can record and schedule messages and perform other system functions. An extensive menu of scheduling and control options would also be desirable in order to provide users with maximum flexibility in scheduling individual announcements and in configuring the system as a whole to meet the demands of specific applications. It would be desirable to be able to connect an automated announcement system to an existing paging or public address system that allows live announcements to be made through a microphone or telephone, such as a conventional public address amplifier or a telephone private branch exchange (PBX), while avoiding interference between the live and recorded announcements. Finally, it would be desirable to have the capability of playing audio messages over a paging or public address system while providing corresponding information on a visual display, or to realize the flexible scheduling features of the above-mentioned audio announcement system in a system which only displays messages.